1. Field of the Invention
The present invention relates to a heat generating element, particularly for an electrical heating device of a motor vehicle, with a positional frame, which forms a receptacle in which at least one PTC element is accommodated, and two contact plates abutting on oppositely situated sides of the PTC element.
2. Description of the Related Art
Such heat generating elements are generally known as a constituent part of an electrical heating device, particularly for heating air in a motor vehicle, whereby such an electrical heating device is likewise to be further developed with the present invention. The heat generating element forms a layer of a layer structure, which normally comprises corrugated-rib elements that abut on both sides of the heat generating element. This layer structure normally has a multiple number of layers of corrugated-rib elements and heat generating elements, whereby the layers are in any case layered one above the other in one plane.
EP 1 768 457 A1 and EP 1 768 458 A1, for example, can be seen as generic. EP 0 350 528 also discloses a type-defining heat generating element as a part of an electrical heating device for heating air.
The suggestions originating with the applicant as stated in EP 1768 457 A1 and EP 1 768 458 A1 specify heat generating elements and electrical heating devices having such that are suitable for operation with high currents in an improved manner. In this context, it is important to enlarge the air clearances and creep paths. Furthermore, it is necessary to ensure a good insulating support of the elements that conduct the power current to the PTC elements within the heat generating element and within the electrical heating device. For example, with the solution suggested in accordance with EP 1 768 457 A1, a heat generating element is specified in which on the outside, the contact plates are covered by an insulating layer that is adhered to the positional frame fully circumferentially. This is intended to prevent the ingression of moisture and contamination into the heat generating element.
The latter presented solution can, however, only exhibit the desired effect if the sealing of the receptacle for the PTC element or PTC elements is sealed reliably with respect to the atmosphere. The object of the present invention is consequently to specify a heat generating element and an electrical heating device that are suitable for operation with high currents in an improved manner in practice. The present invention furthermore intends to create a method for the manufacture of such an electrical heating device.